Diseases and conditions that cause the destruction of cartilage within the joints poses a significant public health concern, particularly in view of the demographics of an aging population. The articular cartilage of the joint represents a complex system of many different molecules. Multiple mechanisms are involved in the degradation of articular cartilage in arthritides such as rheumatoid arthritis (RA) and osteoarthritis (OA). OA, a non-inflammatory arthritis, is the most common form of joint disease, and is second only to cardiovascular disease as a cause of early retirement and disability. Some individuals exhibit OA in a single or limited number of joints, such as may result from traumatic injury due to accident or surgery. Many other individuals suffer from OA in multiple joints due to wear and tear associated with aging or with athletic or occupational activity over an extended period of time. RA is the most common form of inflammatory arthritis, affecting 3% of women and 1% of men. The majority of RA patients have symptoms in multiple joints, especially the small joints of the hand, the elbows, the wrists and the shoulders.
The destruction of hyaline articular cartilage is the hallmark of OA and disabling RA. Although various therapeutic approaches may provide relief of symptoms, no therapeutic regimen has been proven to retard progression of articular cartilage degradation. The progressive deterioration and loss of articular cartilage leads to an irreversible impairment of joint motion. These changes in cartilage are the final pathogenic events that are common to osteoarthritis (OA) and rheumatoid arthritis (RA).
Cartilage destructive processes may also be associated with or initiated by surgical procedures of the joint. Arthroscopy is a surgical procedure in which a camera, attached to a remote light source and video monitor, is inserted into an anatomic joint (e.g., knee, shoulder, etc.) through a small portal incision in the overlying skin and joint capsule. Through similar portal incisions, surgical instruments may be placed in the joint, their use guided by arthroscopic visualization. As arthroscopists' skills have improved, an increasing number of operative procedures, once performed by “open” surgical technique, now can be accomplished arthroscopically. Such procedures include, for example, partial meniscectomies and ligament reconstructions in the knee, shoulder acromioplasties and rotator cuff debridements and elbow synovectomies. As a result of widening surgical indications and the development of small diameter arthroscopes, wrist and ankle arthroscopies also have become routine.
Throughout each arthroscopy, physiologic irrigation fluid (e.g., normal saline or lactated Ringer's) is flushed continuously through the joint, distending the joint capsule and removing operative debris, thereby providing clearer intra-articular visualization. U.S. Pat. No. 4,504,493 to Marshall discloses an isomolar solution of glycerol in water for a non-conductive and optically clear irrigation solution for arthroscopy. Conventional physiologic irrigation fluids do not provide analgesic, anti-inflammatory or anti-cartilage degradation effects.